Services such as Google Maps are capable of displaying street level images of geographic locations. These images, identified in Google Maps as “Street Views”, typically comprise photographs of buildings and other features and allow a user to view a geographic location from a person's perspective as compared to a top-down map perspective.
The street level images tend to be taken at discrete locations. The Google Maps service provides a variety of mechanisms that allow a user to change from street level image at one location to another, such as clicking an arrow icon.
The Google Maps service also shows an animated transition between two street level images. For example, if the user indicates that he or she wants to move forward to the next image, the client computer is provided with instructions to zoom into the current street level. The zooming is intended to convey the impression of travelling into the image. Similarly, if the user moves to the next street level image, the currently-displayed image pans to the right or left, respectively.
The animation of the current street level image may be shown semi-transparently over the next street level image. More specifically, the next street level image is first sent in a low resolution JPEG format, and the current street level image moves across the low quality image while a higher resolution version of the next image is loaded. When the current street level image is finished moving or zooming, it is hidden from the user, at which point the second street level image is displayed.
If the server has access to street level images taken at locations between the geographic location of the current street level image and the location of the street level image to be displayed, the server may send these images to the client computer for display. While advantageous in many circumstances, many client computers lack a sufficiently fast connection to the server to receive and display the intervening images.